Podcast
Questions and Answers
What is the UL, LLC requirement for ground-fault circuit interrupters regarding tripping?
What is the UL, LLC requirement for ground-fault circuit interrupters regarding tripping?
Which of the following are common shock severity factors for humans? (Select all that apply)
Which of the following are common shock severity factors for humans? (Select all that apply)
What is a device intended for the protection of personnel that functions to deenergize a circuit when a current to ground exceeds the values established for a Class A device?
What is a device intended for the protection of personnel that functions to deenergize a circuit when a current to ground exceeds the values established for a Class A device?
Ground-fault circuit interrupter
Ground-fault circuit interrupter protection is available in which types of equipment or products? (Select all that apply)
Ground-fault circuit interrupter protection is available in which types of equipment or products? (Select all that apply)
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What is the operating imbalance threshold that a ground-fault circuit interrupter operates on?
What is the operating imbalance threshold that a ground-fault circuit interrupter operates on?
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Ground-fault circuit-interrupter protection is required for receptacles installed within how many feet of a sink in a dwelling unit? (Select all that apply)
Ground-fault circuit-interrupter protection is required for receptacles installed within how many feet of a sink in a dwelling unit? (Select all that apply)
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In older existing installations without equipment grounding conductors at the outlets, which is acceptable for receptacle replacements? (Select all that apply)
In older existing installations without equipment grounding conductors at the outlets, which is acceptable for receptacle replacements? (Select all that apply)
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What provides a method for installing an equipment grounding conductor for receptacles that are being replaced at a location where one is desired but is not present?
What provides a method for installing an equipment grounding conductor for receptacles that are being replaced at a location where one is desired but is not present?
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Where installed in dwelling unit kitchens, all 125-volt, single-phase, 15- and 20-ampere receptacles that are installed to serve what shall be GFCI protected? (Select all that apply)
Where installed in dwelling unit kitchens, all 125-volt, single-phase, 15- and 20-ampere receptacles that are installed to serve what shall be GFCI protected? (Select all that apply)
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What contains the requirements for ground-fault protection for personnel using temporary power?
What contains the requirements for ground-fault protection for personnel using temporary power?
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What is generally required for grounded electrical services and feeders of more than 150 volts to ground but not exceeding 1,000 volts phase-to-phase?
What is generally required for grounded electrical services and feeders of more than 150 volts to ground but not exceeding 1,000 volts phase-to-phase?
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What is defined as a system intended to provide protection of equipment from damaging line-to-ground fault currents?
What is defined as a system intended to provide protection of equipment from damaging line-to-ground fault currents?
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What does Section 230.95 require regarding ground-fault protection?
What does Section 230.95 require regarding ground-fault protection?
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What is the maximum setting for ground-fault protection of equipment?
What is the maximum setting for ground-fault protection of equipment?
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What voltage and phase arrangement requires ground-fault protection of equipment?
What voltage and phase arrangement requires ground-fault protection of equipment?
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To whom is a record of performance testing of ground-fault protection required to be made?
To whom is a record of performance testing of ground-fault protection required to be made?
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In health care facility power systems, the additional level of GFPE is not permitted on the load side of what?
In health care facility power systems, the additional level of GFPE is not permitted on the load side of what?
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What does a zero-sequence-type GFPE typically consist of?
What does a zero-sequence-type GFPE typically consist of?
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What is the maximum time-delay for ground-fault currents that exceed 3,000 amperes?
What is the maximum time-delay for ground-fault currents that exceed 3,000 amperes?
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Which sections require ground-fault protection of equipment to be performance tested when first installed on site? (Select all that apply)
Which sections require ground-fault protection of equipment to be performance tested when first installed on site? (Select all that apply)
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What is one significant difference between ground-fault circuit interrupters and ground-fault protection of equipment?
What is one significant difference between ground-fault circuit interrupters and ground-fault protection of equipment?
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Which of the following is not a requirement of the NEC for GFPE installed in service equipment as part of a new construction project?
Which of the following is not a requirement of the NEC for GFPE installed in service equipment as part of a new construction project?
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In wet procedure locations of health care facilities, which type of protective equipment is required when GFCI protection cannot be installed?
In wet procedure locations of health care facilities, which type of protective equipment is required when GFCI protection cannot be installed?
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Study Notes
Ground-Fault Circuit Interrupters (GFCI)
- Class A GFCIs trip when continuous 60-hertz differential current exceeds 6 mA and do not trip below 4 mA.
- Common shock severity factors for humans include the amount of current, frequency, duration, body path, and person size.
- GFCIs protect personnel by de-energizing circuits when current to ground exceeds specified Class A values.
- GFCI protection is available in circuit breakers, cord sets, outlet devices, and plug-in adaptors.
GFCI Operation and Installation
- GFCIs monitor supply and return current conductors for imbalances exceeding 4 to 6 mA.
- GFCI protection is required for receptacles within 3, 5, or 6 feet of sinks in dwelling units.
- Existing installations can replace non-grounding receptacles with GFCI devices, marked "No Equipment Ground," or replace with grounding-type receptacles through GFCI devices, marked accordingly.
Equipment Grounding Conductors
- Section 250.130(C) allows for installing grounding conductors where none exist during receptacle replacements.
- GFCI protection is mandated for receptacles serving countertop surfaces or within 6 feet of sink edges in kitchens.
Regulations and Standards
- NEC 590.6 details ground-fault protection requirements for temporary power at construction sites.
- Ground-fault protection of equipment is required for grounded electrical services over 150 volts to ground, not exceeding 1,000 volts phase-to-phase.
- Service disconnects rated 1,000 A or more must comply with Section 230.95, requiring ground-fault protection.
Technical Specifications
- Maximum setting for ground-fault protection of equipment is 1,200 A, with a one-second delay for currents over 3,000 A.
- Voltage systems requiring protection include 480Y/277V, 3-phase, 4-wire, wye-connected configurations.
- Performance testing of ground-fault protection equipment is mandatory upon installation, with records kept for the authority having jurisdiction.
Additional Context
- Health care facilities must not place additional ground-fault protection on the load side of essential system transfer switches.
- Neutral-ground strap type systems monitor ground-fault currents at the main bonding jumper.
- Zero-sequence-type protection components include a current sensor around all conductors, a ground-fault relay, and a shunt-trip circuit breaker.
Key Differences Between GFCI and GFPE
- GFCIs focus on providing protection to individuals, while ground-fault protection of equipment safeguards electrical devices.
- Performance testing, while necessary for GFPE upon installation, can utilize push-button testing rather than primary injection testing as per NEC requirements.
Special Requirements in Healthcare
- In critical areas where GFCIs cannot interrupt power, isolated power systems are mandated for patient safety, as specified in section 517.160.
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Description
Test your knowledge on Ground-Fault Circuit Interrupters (GFCI) and Ground-Fault Protection of Equipment (GFPE) through this set of flashcards. This lesson covers critical aspects like tripping requirements and shock severity factors relevant to electrical safety.
